A Luciferase-Reporter Gene-Expressing T-Cell Line Facilitates Neutralization and Drug-Sensitivity Assays That Use Either R5 or X4 Strains of Human Immunodeficiency Virus Type 1

Abstract

We describe the production and properties of a permanent cell line, CEM.NKR-CCR5-Luc. This line is a derivative of the CEM.NKR-CCR5 line, stably transfected to express the luciferase reporter gene under the transcriptional control of the HIV-2 LTR. Thus the cells respond to Tat expression during HIV-1 infection by producing luciferase, a protein that can be readily and accurately quantitated in a luminometer. The CEM.NKR-CCR5-Luc line expresses both the CCR5 and CXCR4 coreceptors and can therefore be infected with a range of HIV-1 isolates, irrespective of their tropism properties. This is true of HIV-1 isolates from several genetic subtypes and also of a group O isolate. Furthermore, luciferase expression is also activated by infection of the cells with SIVmac239 or SIVmac251. We show that the CEM.NKR-CCR5-Luc cells can be used in assays of HIV-1 neutralization and also for identifying inhibitors of HIV-1 entry targeted at the CCR5 and CXCR4 coreceptors. The luciferase end point simplifies the performance of neutralization and inhibitor-screening assays compared to the use of more conventional end points such as the detection of extracellular p24 antigen.